fisher



Feb. 21, 1956 F. F. FISHER 2,735,294

APPARATUS FOR TESTING THE EFFECTIVENESS OF TUBE ROLLING Filed NOV. 19,1951 INVENTOR.

FRANK F. FISHER BY WW1, y 6% ATTORNEYS United States Patent APPARATUSFOR TESTING THE EFFECTIVENESS 0F TUBE ROLLING Frank F. Fisher, Detroit,Mich, assiguoa' to The Airetool Manufacturing Company, Springfield,{)hio, a corporation of Ohio Application November 19, 1951, Serial No.257,105

12 Claims. (Cl. 73-88) The present invention relates to apparatus fortesting the elfectiveness of tube rolling.

At the present time tube rolling equipment is available for expandingthe ends of tubes into openings in tube sheets or headers and'thisequipment may be associated with control mechanism for insuringuniformity of tube rolling. A typical example of tube rolling equipmentand a control system therefor is shown in my prior Patent No. 2,355,852,wherein means are provided responsive to current supplied to a motor foractuating the tube rolling equipment, adapted to terminate the tuberolling operation when the current reaches a predetermined value.

Thus, in effect, the tube rolling operation is controlled automaticallyso as to produce substantially identical results on each tube as its endis expanded into interlocking engagement in the hole in the tube sheet.Moreover, the control instrumentality is adjustable so that it may beset to produce the optimum holding strength and stability of the rolledjoint. It will be understood that tube joint strength will decrease iftube expansion is either increased or decreased from its optimum value.

When employing equipment of this sort it is of course desirable to checkthe results of the tube rolling operation so as to insure proper settingof the control instrumentality so as to produce optimum results.

It isan object of the present invention to provide apparatus, and moreparticularly, simple hand operated apparatus, for checking theeffectiveness of a tube rolling operation. Thus, in setting the controlinstrumentality for the tube rolling equipment, sample tubes are rolledinto a test block and the results checked and measured to be sure thatthe setting of the control instrumentality is such as to produce optimumresults.

More specifically, it is an object of the present invention to producesimple and easily operated apparatus designed to check the amount offorce required to remove an expanded tube end from a hole in a testblock.

It is a further object of the present invention to provide apparatusefiective to produce a direct indication of the eifectiveness of a tuberolling operation in expanding the metal of a tube end into annulargrooves provided in a hole in a test block.

It is a further object of the present invention to provide apparatus fortesting the efiectiveness of a tube rolling operation which comprises atwo-piece test block having an annular groove provided in a hole thereinto permit separation of the pieces of the test block to permitinspection of the rib produced on a tube by the groove in the testblock.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings, wherein:

Figure 1 is an elevational view, partly in section, showing apparatusfor testing the strength of a joint produced by expanding the end of atube in a test block.

Figure 2 is a view similar to Figure 1, illustrating a variation of theapparatus illustrated in Figure 1.

2,735,294 Patented Feb. 21, 1956 Figure 3 is a fragmentary sectionalview illustrating theme of an annular groove in the test block toproduce corresponding ribs in the expanded end of the tube.

Figure 4 is an elevational view of testing apparatus similar to thatillustrated in Figures 1 and 2, used in conjunction with a hydrauliccylinder.

Referring now to Figure 1, there is illustrated a test block Ill havinga cylindrical opening 12 extending therethrough. The test block isdesigned for use with a portion of a tube 14 which is used in the test.In completing the test the end of the tube 14 is inserted into theopening 12 of the block 10 and is expanded into contact with theinterior surface of the hole or opening 12 by suitable tube rollingequipment.

In order to test the effectiveness of the tube rolling operation thereis provided a supporting yoke 16 having arms 18 and 2b which terminatein inwardly extending portions 22 adapted to underlie and support thetest block 10. The support yoke 16 is provided with an enlarged boss 24which is internally threaded to receive a screw 26. The lower end of thescrew as is reduced as indicated at 28, and its upper end is providedwith a suitable head 30 by means of which the screw may be turned with atorque wrench or similar measuring means.

In the embodiment of the invention illustrated in Figure 1 means areprovided connecting the screw 26 to the tube 14 so as to pull the tubeout of the test block 1%. This means comprises a stiffening ring 32which surrounds the lower end of the tube 14. A plunger 34 is providedadapted to extend through the tube 14 and having at its lower end atapered portion 36. Intermediate the tapered portion 36 of the plunger34 and the inner surface of the tube 14 is a split expanding ring 33,the inner surface of which is tapered in conformity with the taperedportion 36 of the plunger 34. The upper end of the plunger 34 isprovided with a head 46 recessed as indicated at 42, for the receptionof the lower end portion 28 of the screw 26. I

In use, a torque wrench is provided with means asso ciated therewith formeasuring the torque applied when the wrench is applied to the head 3-0,and the screw 26 is rotated in a direction tending to move the plunger34 downwardly. Downward movement of the plunger 34 cams the sectionsof'the split ring 38 outwardly, thus gripping the lower end of the tube14. At the same time, a downward pull is applied to the tube 14 tendingto pull the tube out of the hole 12 in the test block It When sufiicienttorque has been applied to the screw to build up the force necessary 0tbreak the joint between the expanded tube end and the test block 10, thereading on the torque wrench indicator will give an indication of theforce which was required to break the joint. Similar tests may be run onother tube sections in which different adjustments have been made in thecontrol apparatus for the tube rolling equipment and thus the optimumsetting of the control instrumentality arrived at.

In Figure 2 there is illustrated a similar arrangement employing many ofthe same parts illustrated in Figure 1, and these parts will not againbe described in detail. In this illustrated embodiment of the inventionmeans are provided for connecting the lower end 28 of the screw 26 insuch a manner as to push the tube 14 downwardly so as to break the jointbetween the tube and the test block 10.

For this purpose an abutment member 56 is provided havthe forcedeveloped by the screw 26 tending to move the tube 14 longitudinally ofthe opening 12 in the block 10 is applied as a push to the upper end ofthe tube 14, rather than as a pull to the lower end thereof.

Preferably, the interior of the hole 12 is a smooth cylindrical holeeven though the rolling equipment is being tested for its effectivenessin carrying out a tube expanding operation in conjunction with aninternally grooved hole. It is found that up to and including theoptimum degree of expanding a substantially definite and invariablerelationship exists between the force required to remove an expandedtube end from a smooth hole and a similarly expanded tube end from ahole provided with grooves of definite shape and number. However, it ispossible, if desired, to provide internal grooves in the hole 12 of theblock 10 in order to obtain the actual strength of joints thus equipped.

As seen in Figure 3, the block 10 may be provided with one or more (andpreferably two) grooves 60, into which the material of the tube 14 isexpanded to produce ribs 62. Obviously, the presence of the rib 62requires a substantially greater force to move the expanded tube out ofthe test block, but as indicated above, this force bears a substantiallyconstant relationship to the force required to move the tube out of asmooth hole, assuming an identical expanding or tube rolling operation.

In Figure 3 the grooves 60 are indicated as of generally V-shape incross-section. It will be appreciated however that grooves of difierentcross-section may be provided in conformity with the types of grooveswhich will be encountered in the actual production tube rolling. Thus,grooves of rectangular cross-section or semi-circular cross-section maybe provided in the test block as required, the rectangular shape beingused more than others.

In the embodiment of the invention illustrated in Fig- 3 ures 1 and 2,the force for moving the expanded tube out of the test block isdeveloped by a torque measuring wrench applied to the screw 26. However,in some cases it is preferable to employ a different power means formoving the tube.

In Figure 4 there is illustrated an arrangement in which the supportingyoke 16 has secured thereto a power cylinder 70 containing a piston 71connected to a piston rod 72. The test block 10 is supported in the yokein the same manner as illustrated in Figures 1 and 2 and a force isapplied to the tube 14 tending to move it longitudinally of the hole inthe test block in the same manner as illustrated in Figures 1 and 2.Thus the lower end of the piston rod 72 may fit within a recess providedin a plunger such as illustrated at 34, associated with the expandingsectional ring 38 and the stiffening ring 32, Alternately, the lower endof the piston rod 72 may cooperate with an abutment member such asillustrated at 56 in Figure 2.

The cylinder 70 has connected thereto a pressure gauge 73 giving adirect indication of the pressure prevailing within the cylinder 70above the piston 71. Connected to the upper end of the cylinder 70 by aconduit indicated at 74 is a pump 75 provided with a manual operatinghandle 76 so that the operator may by manipulation of the handle 76,build up sufficient pressure Within the cylinder 70 to break theexpanded tube loose from the test block 10. It is only necessary for theoperator to watch the gauge 73 as the pressure is increased to determinethe pressure prevailing when the tubes moves with respect to the testblock.

It will be appreciated that in tube rolling optimum re sults areobtained at an intermediate setting of the con trol instrumentality, andaccordingly, it is of the utmost importance to be able to determine byactual tests or inspection when the optimum result is obtained.

The present testing apparatus permits ready testing of the expandedjoint on the job and permits the necessary number of tests to be run todetermine the optimum settingof the control instrumentality.

The drawings and the foregoing specification constitute 4 a descriptionof the improved apparatus for testing the effectiveness of tube rollingin such full, clear, concise and exact terms as to enable any personskilled in the art to practice the invention, the scope of which isindicated by the appended claims.

What I claim as my invention is:

1. Testing apparatus for testing the effectiveness .of

tube rolling comprising a test block having a hole extendingtherethrough from end to end in which a tube is rolled, a support forsaid block extending across one end of said block and including meansengaging the opposite end thereof, means on the portion of said supportextending across said one end thereof and including a member extendinginto and movable axially of the hole in said block, means for connectingsaid member to a tube rolled in the hole in said block at a point beyondsaid block from said one end thereof to apply a pull to the rolledconnection, actuating means for moving said member axially of the holeto free the tube from said block, and means for measuring the forcerequired to move the tube longitudinally of the hole in said block.

2. Testing apparatus as defined in claim 1 in which the means forconnecting said member to the tube comprises a shouldered abutmentelement received in the end of the tube adjacent said member, theshoulder thereon being shaped to engage the end of the tube and to bereceivable within the hole in said block.

3. Testing apparatus as defined in claim 1 in which the means forconnecting said member to the tube comprises a stiffening ringsurrounding the tube at the opposite side of said block from saidmember, said member including a tapered portion movable longitudinallyof the tube, and a sectional expansion ring having a tapered innersurface received in the tube opposite said stiffening ring cooperablewith the tapered portion of said plunger.

4. Testing apparatus as defined in claim 1 in which the actuating meanscomprises a screw threaded to said support axially of the hole in saidblock and means for operatively connecting said screw to said member.

5. Testing apparatus as defined in claim 4 which comprises means forrotating said screw, and means for measuring the torque to said screw.

6. Testing apparatus as defined in claim 5 in which the means forrotating the screw and measuring the torque comprises a torque wrenchincluding torque indicating means.

7. Testing apparatus as defined in claim 1 in which the actuating meanscomprises a powercylinder, a piston therein, a piston rod for movingsaid member, means for forcing fluid into said cylinder, and a gauge forindicating pressure of fluid in said cylinder. v

8. Testing apparatus as defined in claim 1, the interior of said holebeing smooth. t

9. Testing apparatus as defined in claim 1, the interior. of said holehaving an annular groove therein. r

10. Testing apparatus for testing the effectiveness of tube rollingcomprising a test block having a hole therein provided with an internalannular groove into which a tube is expanded by rolling, and means fordetermining the eifectiveness of the rolling operation in producing ribsconforming to said grooves comprising means'for forcing the tube out ofsaid block and means for measuring the force required to free the tubefrom said block.

ll.-Testing apparatus for testing the efiectiveness 0 tube rollingcomprising a test block having a hole extending therethrough from end toend in which a tube is rolled, a support for said block extending acrossone end of the block and including means engaging the opposite endthereof, means on said support including a threaded membermovableaxially of the hole in said block upon rotation thereof, meansextending at least in part into the tube for connecting said threadedmember to the tube in said test/block, and a torque wrench for rotatingsaid threaded member.

12. Testing apparatus as defined in claim 11 in which 5 said meanscomprises a headed element having a shoulder engageable with the end ofsaid tube and a seat for receiving the end of said threaded member toapply forces tending to push the tube out of said block upon rotation ofsaid threaded member.

References Cited in the file of this patent UNlTED STATES PATENTS1,026,548 Allien May 14, 1912 6 Mohrman Aug. 22, 1922 Liddell Mar. 13,1923 Lloyd Feb. 12, 1924 Clark Jan. 12, 1926 Strachauer et a1 Dec. 24,1929 Rummer Aug. 12, 1941 Swyers Feb. 20, 1945 Sakirsky Dec. 26, 1950Clifiord et a1 Apr. 15, 1952

